Viscosity reduction of petroleum mahogany sulfonate hydrocarbon solutions



tions are to'be used. There are,

Patented Nov. 30,

FFKCE VESCUSHTY REDUCTION or PETROLEUM MMQGANY SULFONATE HYDROCAR- EONSOLUTIONS Abraham Moscowitz, New llork, N.

L. Sonneborn Sons, lInc.,

ware

No Drawing. Application November Y., assignor to a corporation oi. Dela-Seriai No. 711,476

8 @laims. (Cl. 260-504) This invention relates to new and usefulimprovements in the viscosity reduction of petroleum mahogany sulfonatehydrocarbon solutions.

Petroleum mahogany sulfonate solutions in organic solvents of the waterimmiscible type are used for a variety of purposes such as wettingagents, emulsifying agents and the like. Ordinary petroleum mahoganysulfonates impart to their solutions a. relatively high viscosity. Insome cases this high viscosity-is not criticalregarding the purpose forwhich the sulfonate soluhowever, many cases in which a relatively highviscosity is undesirable or detrimental to their intended use orapplication. This is, for example, true in textile processing such as01' wool, worsted, rayon, viscose or the like in which the variousprocessing steps involved in the conversion of the raw materials intofibres, the formation of the fibres into threads and the weaving of thethreads into fabric, require the presence of a lubricating agent havinga Saybolt viscosity of below 600 and preferably below 300 secondsSaybolt at 100 F. The latter is particularly true of textile lubricantsused in the processing of synthetic fibres. In the case of textileprocessing it is for instance desirable to have a hydrocarbon textilelubricant composition with a sulfonate content of in excess of 28%mahogany sulfonate so as to render the composition not only readily andspontaneously emulsifiable but also to make the same readily wettable orrewettable on the fibre to thereby impart to the textile materialsubstantial selfscourability. Hydrocarbon solutions of the textilelubricant type and containing in excess of 28% of petroleum mahoganysulfonates possess. however, a viscosity far in excess of 600 secondsSaybolt at 100 F. and usually a viscosity in excess of- 1000 secondsSaybolt at 100 F. For this reason it has been in the past necessary insuch cases to limit the sulfonate content to a maximum of approximately15% in order not to exceed the usable viscosity for textile materialtreating purposes. Another example is the use of petroleum mahoganysulfonates in the compounding of cutting oil bases in which therelatively high viscosity and tackiness imparted to the composition bythe sulfonates is an undesirable aspect interfering in many respectswith the proper ease of application and use.

The relatively high viscosity of petroleum mahogany sulfonates inorganic solvents is normally not subject to reduction by the addition ofrelatively low viscous diluents or thinning agents. This requires agentsof such relatively low viscosity that they interfere with thelubricating properties of the composition. Furthermore, these solventsare then of the type which easily evaporate. This is particularlycritical in the case of textile treating materials since the use of suchthinning solvents will leave behind on the fibre upon evaporation aviscous sticky im pregnant without adequate lubricating capacity on thefibre and will also interfere with the scourability of the impregnatedmaterial. On the other hand thinning with a solvent of the lubricanttype diluent will not obtain the desired result as it is necessary toadd so much of the diluent as to bring the sulfonate content to belowthat necessary for adequate emulsiflcation or other purpose for whichthe composition is designed.

Certain treatments of petroleum mahogany sulfonate hydrocarbon solutionswith hypochlorites or chlorites are accompanied by a viscosityreduction. Thus for instance a viscosity reduction is obtained bysubjecting a petroleum sulfonate product dissolved in a hydrocarbon,including a hydrocarbon of the mineral oil type (for example retainedo'il conventionally derived from the acid refining of a petroleum oildistillate), to a treatment with sodium hypochlorite or sodium chloriteuntil a Lovibond value of less than 8R and preferably about 2-3R 10%while oil solution /2" cell) is obtained. This is, for instance, setforth respectively in U. S. Patent 2,201,119 issued to M. Blumer et al.,and U. S. Patent 2,307,743 issued to L. Liberthson et al. Thehypochlorite treatment requires relatively large amounts of hypochloritefor which reason undesirably large amounts of inorganic saltsimay beproduced as a result of the reaction, necessitating salt removalpurification. Furthermor in many cases the hypochlorite treatment doesnot produce as efllcient or as low a viscosity reduction as may bedesired. This would apply, for instance, where a petroleum mahoganysulfonate textile lubricant composition is to be used for syntheticfibre processing, in which case a viscosity below 300 seconds Saybolt atF. for a sulfonate content of in excess of 28% is desirable. On theother hand, the chlorite treatment, though somewhat more effective inviscosity reduction of suitable petroleum mahogany sulfonate hydrocarbonsolutions, has to be carried out at an acid pH and necessitatesneutralization of the resultant chloritetreated product. Suchneutralization, however, is in many cases accompanied to some extent bya viscosity reversion, i. e., an increase of the viscosity from that ofthe acidified treated solufilling practice.

eflicient than either thehypochlorite or chlorite treatment, and willpermit the reaction to be carried on at an acid or alkaline pH. 1!carried out at an alkaline pHthe disadvantage of viscosity reversionupon neutralization from an acid pH is completely eliminated. Ifoperating at an acid 'sulfonate organic solvent solution which is morepH such viscosity reversion in this case is relatively negligible. Atthe same time when proceeding in accordance with my discovery it ispossible to operate in such a manner that such inorganic residue as maybe produced by reason of the treatment is relatively small and may inmany cases be disregarded without substantially impairing the functionsor properties of the sillfonate in solution for the particularcomposition for which it is desired. In this manner inorganic saltremoval or purification is unnecessary.

In accordance with the invention a suitable petroleum mahogany sulfonatesolution in an organic substantially water immiscible solvent for saidsulfonate isreacted with an alkali metal chlorite and an alkali metalhypochlorite in amount and for a period of time sufllcient toappreciably reduce the normally relatively high viscosity of saidsolution due to the sulfonate dissolved therein and preferably reducesaid viscosi- 1:5! by at least one-third.

The solvents that may be used for this purpose should be substantiallyneutral tochlorite and/or hypochlorite action, should not appreciablydissolve inorganic salts and should be substantially liquid at normaltemperatures. Suitable solvents that may be used in the practice of theinvention are, for instance, petroleumoil distillates or any fractionthereof, benzol and its homologs, naphtha, carbon tetrachloride,tetrachlorethane, chloroform, etc., and in general any aromatic oraliphatic or aryl or aralkyl hydrocarbon or hydrocarbon mixtureincluding their halogenated derivatives of the aforedescribed characterand nature. In many cases, particularly where the solvent is to beremoved after the.

viscosity reducing treatment, it is desirable to have the boiling rangeof such solvent sumcient- 1y low to permit removal in the customarymanner such as by distillation in vacuo or otherwise without causingthereby any decomposition of the mahogany sulionates. In such cases itis of advantage that the boiling point he so low and preferably between75 and 250 F. as to enable the removal of the solvent at ordinarytemperatures without the necessity of resorting to vacuum distillation.

lectively referred to as mahogany petroleum sulionic acids. These arerecovered from the oil layer in accordance with conventional methods inthe form of solutions of these sulfonic acids or their salts (the latterbeing collectively termed petroleum mahogany sulfonates) in a portion ofthe oil relatively tenaciously occluded by these sulfonic bodies, Thisoccluded oil is generally referred to in the art as "retained oil. Thepetroleum sulfonic acids or sulfonate oil compositions normally containabout 30 to 35% of retained oil and to of the petroleum mahoganysulionic material. Depending upon the type" and origin of petroleum oildistlllates from which these sulfonate-oil solutions or stocks arederived they contain sulfonates of varying averaged molecular weights.For convenience therefore the sulfonate stocks are identified by theiraverage molecular weights. Thus, a 420 or 450 sulfonate stock is a stockin which the sulfonates have an average molecular weight of 420 or 450respectively.

It, is possible to carry out the chlorite-hypochlorite reaction ateither an alkaline or acid pH. Excess alkalinity or acidity should beavoided, however, as they are detrimental to the efdciency of theviscosity reduction and may furthermore give rise --to partialdecomposition of the sul- "fonates and an undesirable colordeterioration rather than color improvement in the resultant products.For reasons of viscosity reversion upon neutralization, thoughrelatively small, it is pre- 'ferred to carry on thechlorite-hypochlorite treatment at a neutral toalkallne pH and withinthe preferred embodiment of the invention a pH range from 7.5 to 8.5 isreconmienged.

'In the practical application of the invention, a

suitable petroleum mahogany sulfonate solution is intimately contactedwith an alkali metal chlorite and an alkali metal hypochlorite. In thepreferred mode of such treatment 1.5 to 7% and preferably 2.5 to 6% ofthe chlorite and hypochlorite (calculated on the'aggregate dry weight bywe'ightof sulfonate in solution) are used in a. proportion of 0.5 to 4parts by weight and preferably of 2 to 3 parts by weight of hypoehloritefor every one part by weight of chlorite. The reaction is continueduntil the desired viscosity reduction is obtained. If necessary, thesolution may be acidified with H2804 to the desired pH range. Thepreferred procedure is to dissolve the chlorite in the aqueoushypochlorite solution.

The temperature of reaction is ordinarily not critical. The reaction,however, may be facili- The petroleum mahogany sulfonate which issubjected to the viscosity reduction is normally one derived from theacid refining, with fuming sulfuric acid, of a petroleum oil distillatestock under sulfonating conditions of acid amount and temperature inaccordance with conventional re- In such, conventional fuming sulfuricacid refining an oil layer and acid sludge layer are formed, the formercontaining dissolved therein petroleum mahogany sulionic acids coltatedby increasing the temperature to for example a preferred temperature offrom 120 to 200 F. This is particularly desirable with more heavilyviscous solutions as the higher temperature will increase the fluidityof the solution, thus permitting more intimate contact between thereactants.

The extent to which low viscosity values may be obtained depends, atleast to some extent, upon the type or origin of the petroleum mahoganysulfonate selected for the treatment. Ordinarily higher averagemolecular weight sulfonates possess a higher viscosity and the resultingviscosity after treatment is usually commensurately higher than theviscosity after treatment of a comparative sulfonate hydrocarbonsolution which before treatment possessed a relatively lower viscosityand in which the sulfonate had a lesser average molecular weight.

The ratio of petroleum mahogany sulfonate to solvent is, as a rule, notcritical except that it is desirable to so adjust the ratio that theviscosity of the solution is sumciently low at the desired or selectedtemperature of treatment to permit the intimate contact between thereactants. In most cases, however, a ratio of mahogany sulfonate tosolvent of substantially 2 to 1 (by weight) will give satisfactoryresults. sulfonate concentrations above 70 to 75% sulfonate content arenormally not desirable for direct reaction without suitable extension.As a mode of agitation, any conventional method such as stirring,air-blowing, shaking, etc. may be used- As above pointed out, theviscosity reducing reaction in accordance with the invention may becarried out with an organic solvent solution containing relatively highconcentrations of petroleum mahogany sulfonate. In this case theresultant product is a concentrate which in many cases must bethereafter adjusted by the addition of organic solvent material ofsuitable viscosity, such as a suitable lubricant hydrocarbon, to therequisite petroleum mahogany sulfonate content desired for the specificpurpose for which the composition is to be used. Thus, for instance, ifit is desired to ultimately produce a textile treating oil having inexcess of 28% petroleum mahogany sulfonate and a viscosity of less than600 seconds Saybolt at 100 F., a concentrate having in excess of 40% andusually between 60 and 65% sulfonate, is first obtained after theviscosity reducing reaction in accordance with the invention, whichproduct may be then extended by the addition of a suitable lubricanthydrocarbon such as a mineral pale oil having a viscosity of 75 secondsSaybolt at 100 F. to a sulfonate content between 28 and 40% and aviscosity below 600 seconds Saybolt at 100 F.

Alternatively, the viscosity reducing reaction may be carried out withan organic solvent solution of a petroleum mahogany sulfonate alreadypossessing the requisite final sulfonate content desired and intendedfor the purpose for which the viscosity reduced product is to be used.In that case it is also of advantage to select for the solution suchsolvent as is desired for the final product, i. e., if a textilelubricating oil is intended to be ultimately obtained a textilelubricant, having, for instance, a viscosity between 40 and 150 secondsSaybolt at 100 F. is selected as the solvent for the sulfonate. Theproduct resulting from the viscosity reducing treatment is then per seusable after such further refining or purification as may be requiredfor a textile treating oil.

Though in the operation of the novel viscosity reducing process any ofthe aforementioned solvents may be used with advantage, I prefer to useas the solvent that hydrocarbon fraction, the acid refining of whichfurnished the crude mahogany sulfonate stock and which is carried asretained oil. The crude mahogany sulfonate-retained oil stockconstitutes as sucha convenient mahogany sulfonate solution that may beto treatment in accordance with the invention.

Instead of adding in the operation of the invention hypochlorite per seas a component of the hypochlorite-chlorite combination, it is possible,if desired, to produce the hypochlorite or other, hypochlorousequivalent in situ in the solution through the stoichiometricinteraction of chlorine and an aqueous and/or alkaline medium.

Whenever carrying out the viscosity reducing procedure in accordancewith the invention in a manner yielding directly a usable product of asulfonate content reduced viscosity and type of solvent per se usablefor a predetermined purpose, this may be also accomplished by amodifisubjected directly cation of the conventional acid refining. Inthis case the solvent is necessarily the oil, the acid refining of whichwill furnish the mahogany sulfonate stock. When proceeding in thismanner a petroleum oil distillate is given at a temperature of about 150F., a 50% batch treatment with fuming sulfuric acid, 1. e., a treatment(sometimes in several batches) with 50% of acid by weight of the oiltreated. The cooled acidified oil is thereafter diluted with an equalvolume of benzol or benzol homolog, the mixture is permitted to settleovernight and the acid sludge layer is withdrawn. After neutralizing theoil layer and removing the benzol by distillation, the oil layer issubjected to the viscosity reducing reaction in accordance with theinvention. The resulting product contains approximately of petroleummahogany sulfonates, about 70% of lubricant mineral oil (of the textilelubricant usable type) and possesses a viscosity below 600 secondsSaybolt at 100 F.

Once a'petroleum mahogany sulfonate has been subjected in suitablesolvent medium to a viscosity I reducing reaction in accordance with theinvention, it is possible to remove the solvent if desired and recoverthe petroleum mahogay sulfonates as such substantially free fromsolvent. These sulfonates when redissolved in the solvent still exhibitin solution the same reduced viscosity which they possessed prior to theremoval of the of illustration and'not stock (containing 61 -2% solvent.

The following examples are furnished by way of limitation.

,Ezample I 100 lbs. of petroleum sulfonate-retained oil soduimsulfonates) were heated to 120 F.; a solution of 1 lb. sodium chloritein 5 lbs. aqueous hypochlorite solution having a 10% available chlorinecontent was added. The mixture was heated to 200 F. and maintained atthis temperature, while stirring, for

- one-half hour, then blown with air to drive out and a Lovibond colorretained moisture and diluted with 75 viscosity mineral oil to a 30%sulfonate content. Before treatment, the petroleum sulfonate-retainedoil stock had a viscosity of 163 furol at 210 F. and upon dilution to a30% sulfonate content 1463 saybolt at 100. After treatment and beforedilution the corresponding viscosity was 113 furol at 210 F. and afterdilution 375 Saybolt at F.

Example II 100 lbs. of a etroleum mahogany sulfonate stock containing61-2% sulfonate and 38% retained oil was used. The a Mid-Continentdistillate subjected to white oil refining with fuming sulfuric acidunder sulfonating conditions. The mahogany sulfonates in the stockpossessed an average molecular weight of 450, a furol viscosity of 144seconds at 210v F. value of about 8E (10% white oil solution /2" cell).1 lb. of .sodium chlorite was dissolved in 2.5 lbs. of an aqueous sodiumhypochlorite solution having an available chlorine content ofapproximately 10%. This chlorite-hypochlorite solution was then added tothe sulfonate stock, whereupon the mix was agitated, maintaining thetemperature at about 180 to 200 F. The pH was adjusted to about 8 andthe treatment was continued until a sample showed a reduced Lovibondcolor (10% white oil solution /2" cell) of about 2-3R, which wasachieved after about one-half hour. After treatment the reducedviscosity was 73 furol at 210 F. and after dilution with a mineral pale0111(75 stock was obtained from v 7 --seconds Saybolt at 100 F.) to asulionate content a viscosity of 400 seconds Saybolt at 100 F. 7

Example III 100 lbs. of a Mid-Continent distillate containing about 30to sulfonatables was treated at about 150 F. with about 50 ;lbs. offuming sulfuric acid. After completion of the addition of the andsulfonate content respectively as against the viscosities of the samestock treated in accordance with the invention and of 30%, 35% and 4.0%sulfonate content dilutions for each treated stock. The treatment ofeach stock was carried out as specified in Examples I or II. Theextending oil in each case was a neutral solvent refined mineral paleoil having a Saybolt viscosity of 75 or seconds at 100 F. as specified.

Viscosity Reduction Obtained byg gw e g'ae uaes Ohlorite-Hypochlorite enxten Type of s'momte Stock Per gent Furol With 76 vis. neutral to odiumVis. at Sodium Sulion. Cont. Saybolt Viscosities at Seybolt Viscositiesat Sulionate 210 F. Furol 100 F. When Extended 100 F. When Extended Vis.at With 75 via. neutral to With 60 via. neutral to 210 F. Sodium Sulfon.Cont. Sodium Sulion. Cont.

Av. M01. 8

wt ource 30% 35% 40% 30% 36% 40% 30% 35% 40% too Gulf Coast 62 205 1,500 1,750 2,100 110 415 550 sec Q. 450 Mid. Cont 02 144 l, 100 1,2801,475 73 400 495 575 420 Penna 62 81 910 1,050 1, 200 30 380 475 560 185240 285 acid, the oil was permitted to cool and the cooled, acidifiedoil was thereafter diluted with an equal volume of benzol. The mixturewas then permitted to settle overnight, whereupon the acid sludge layerwas withdrawn. The oil layer was then neutralized with an aqueouscaustic solution of about 27 B. After settling the aqueous spent causticlayer was removed; whereupon the oilbenzol layer was subjected todistillation for the removal of the benzol. There was then added to theresulting mahogany petroleum hydrocarbon solution achlorite-hypochlorite solution prepared by dissolving 0.5 lb. of sodiumchlorite in 1.25

Example IV 50 lbs. of the same 62% sulfonate stock specified in ExampleII were extended with 52 lbs. of a 75 seconds Saybolt viscosity (at 100F.) pale oil to yield a 30% sulfonate content. There was then added tothe resultant product having a viscosity of 1100 seconds Saybolt at 100F., 0.5 lb. sodium chlorite dissolved in 1.25 lbs. of an aqueous sodiumhypochlorite solution (10% available chlorine content). Thechlorite-hypochlorite The foregoing description is for purposes ofillustration and not of limitation and it is therefore my intention thatthe invention be limited only by the appended claims or theirequivalents wherein I have endeavored to claim broadly all inherentnovelty.

I claim:

1. Process for reducing the viscosity of petroleum mahogany sulfonatesolutions, which cornprises treating a petroleum mahogany sulfonatesolution in an organic substantially water-immiscible solvent for saidsufonate with an alkali metal chlorite and an alkali metal hypochloritein a proportion of 0.5 to 4 parts by weight of hypochlorite for every 1part by weight of chlorite and in amount and for a period of timesufllcient to appreciably reduce the normally relatively high viscosityof said solution due to the sulionate dissolved therein.

2. Process in accordance with claim 1 in which the treatment is carriedout with an amount of chlorite and hyprochlorite and for a period oftime sufficient to reduce said normally relatively high viscosity ofsaid solution by at least one-third.

3. Process in accordance with ciaim 1 in which said solution is treatedwith said sodium chlorite and hypochlorite combination in amount and fora period of time suflicient to yield a reduction to a Lovibond colorvalue below 8R.

4. Process in accordance with claim 1 in which said solution is treatedwith said sodium chlorite and hypochlorite combination in amount and fora period of time sufficient to yield a reduction to combination wasadded while the mix was agitated and the temperature brought to about180 to 200 F. The pH of the mix was adjusted to about 8 and agitationand the temperature continued until the sample showed a reduced Lovibondcolor of about 2-3R, which was obtained after about one-half hour. Theresultant product contained about 30% petroleum mahogany sulfonate,about 70% mineral oil and a viscosity of about 390 seconds Saybolt at100 F.

In the following table comparative viscosity data are furnished ofvarious sulfonate stocks showing in each case the viscosities of theuntreated stock and of dilutions thereof to 30, 35

a Lovibond color value of about 2-3R.

5. Process for reducing the viscosity of petroleum mahogany sulfonatesolutions, which comprises treating a petroleum mahogany sufonatesolution in an organic substantially water-immiscible solvent for saidsuiionate with 1.5 to 7% aggregate dry weight of alkali metal chloriteand alkali metal hypochlorite by weight of sulfonate in solution in aproportion of 0.5 to 4 parts by weight of hypochlorite for every onepart by weight of chlorite.

6. Process in accordance with claim 5 in which saidchlorite-hypochlorite treatment is carried out at a pH of from '7 to8.5.

7. Process for reducing the viscosity of petroleum mahogany sulfonatesolutions, which comprises treating at a pH of from 7 to 8.5, apetroleum mahogany sulfonate solution in an organic REFERENCES CITED subtantially water-immi ibl lv t for id The following references are ofrecord in the suitonate with an aqueous solution of 1.5. to 7% file ofthis patent: aggregate dry weight of alkali metal chlorite and 5 UNITEDalkali metal hypochlorite by weight of sulionate STATES PATENTS insolution in a proportion of 0.5 to 4 parts by Number Name Date weight ofhypocmorite for every one part by 2,201,119 Blumer et a] May 14, 1940weight of chlorite mberthson Jan. 12,

8. Process in accordance with claim? in which 10 OTHER REFERENCES saidaqueous solution contains said chlorite and Monte m a ratio of 2 to 3parts by weight Article from Technical Assn. Papers-1940- of hypmcmontefor every one part by weight Use of Sodium Chlorite in Bleaching" byTaylor of et 81., pages 251-256.

ABRAHAM MOSCOWITZ. 15

